Inner tube



Patented pr. 29, 1924.

miran sra'rlezsl I NATHANIEL G. WARTH, 0F COLUMBUS, QHIQ.

INNER TU BE.

Application med October 18, 1920. Serial No. 417,677.

To all lwhom t may concern.'

Be it known that I, NATHAmnL G. WARTH, a citizen of the United States,residing at Columbus, in the county of Franklin and State of Ohio, haveinvented a new and useful Inner Tube, of which the following is aspecification.

This invention relates to inner tubesfor use within the casings ofpneumatic tires,

one of the obects of the invention being to provide a ight tube havingcombined therewith a thickness of sticky, plastlc rub-A ber compound orthe like whereby the tube is rendered self healing after beingpunctured.

A further object is to provide a tube of this character in which theinner or exposed surface of the layer of sticky compound has a coatingof ve etable or mineral fiber whlch cooperates wit said compound torovide a plugging or dammingmaterial which w1ll ow with the compound tothe perforation or puncture and aid materially in the closing thereof,and which also .acts as a. mat or covering whereby the pressure of airwithin the infiated tube will result in the shifting of the. compoundover an extended area toward the puncture during the self healingaction. 5

A further object is to provide a fibrous inner coating which serves toprevent the opposed portions of the wall of the tube from lstickingtogether when the tube is deflated or attene y A still -furtherobj'ectf'is to provide a tube having a fibrous inner llayer which willoperate efiicientl y whether the tube is a compression tube, i. e. atube which is placed under annular compression when infiated, or anexpansion tube, i. e. a tube which will stretch when inflated, the saidfibrous coating at no time interfering with either the compression orexpansion of the tube, as would be the case should a fabric, leather, orother coating of sheet material be emploved.

With the foregoing and other objects in view, which will appear as thedescription proceeds, the invention resides in the combination andarrangement of parts and in the details of construction hereinafterdescribed and claimed, it being understood that, within the scope ofwhat is claimed, changes in the precise embodiment of the inventionshown can b e made without departing from the spirit of the invention.

In the accompanying drawings the preferred form of the invention hasbeen shown.

In said drawings- Figure l is a transverse sectionl throu h a portion ofan inner tube constituting t e present invention,A the adjacent part ofthe tire casing being. also shown.

Figure 2 la section on line 2*'2, Figure l through a portion of the tubeand casing and showing the relative positions of the parts prior toinfiation.

Figure 3is a similar view showing the relative positions of the partssubsequent to infiation.`

Fi re 4 is a similar View showin the positions taken by the layers ofthe lnner tube while being punctured.

Figure 5 is a like view showing how the parts are positioned during theywithdrawal of the puncturing device.

Figure 6 is a section showing the healed puncture.

Referring to the figures by characters of reference'l designates thewall of the inner tube formed of cured or vulcanized rubber and appliedto the inner surface of' this wall is a thickness or layer of stickyplastic compound indicated at 2 and which layer can extend either partlyor entirely over the inner surface of the tube wall, it being essential,however, that it be arranged upon the tread and adjacent side portionsof the wall. Vhile thiscompound can be of any of the well known viscousplastic substances either with or without rubber as an ingredient it ispreferred, in the present instance, to combine with the compound afilling of granular material such as cork, comminuted cured rubber oranj other similar substance tending to add bo y tol the compound. It isalso intended to mix with the compound a percentage of loose vegetableor mineral fibers, the entire mixture being thoroughly impregnated withthe compound so that the same will be able to flow properly to apuncture in the manner hereinafter pointed out.

There is provided on the inner surface of the layer 2 an inner coatingof loose fibers of a mineral or vegetable nature which` when the tire isdefiated, will present a soft fiuii'y surface so that when the tube isfiat tened the opposed portions of the wall thereof will not sticktogether. When the tube is infiated, however, the pressure of the airagainst these loose fibers forming the inner '-t-hese matted fibers willresult in equal distribution ofk the fpressure throughout the areal ofthe compoun l When the tube isl punctured by a nail a,

wire or other article the point thereof while passing through the tubewill force the layers of the tube inwardly from .the compressed positionshownY in Figure 3 to the position shown in Figure 4. vAsthe article amoves into vthe tube the sticky compound will adhere thereto and aportion of this compound will travel inwardly with the article a. Owingto the equal distribution of'pressure through the matted libere andagainst `the compound, said compound will be vcaused to flow through aconsiderable area toward the entering object a with the result that 'anexcessive amount of the compound will be brought to position adjacentthe point of' puncture As a result of this action when the object a iswithdrawn, as shown in Figure 5 it will drag a portion of the compoundwith it into the opening that has been formed in the Wall l of the tubeand some ofthe fibers adjacent the pluicture will likewise be drawn bythe com ound intoy the openino. As the compoun includes both ranular andfibrous ingredients they will e ample to thoroughly plug any mediumsized puncture but should the puncture be largei than ordinarily some ofthe fibersgforming the inner coating 3 will be drawn up into thepuncture and insure healing thereof.' As theobject a. is withdrawn fromthe tire casing, indicated at I), said casing being of a hardnon-elastic material will operate to strip from the object all of thecompound, etc., adhering thereto' pressure of the air within the tubeand.

against the matted layer 3 will cause the compoundy to move toward thepoint from which the, object a was withdrawn so that the compound willhere amalgamate or flow together and, at the same time, the adjacentfibers of the'inner coating b will work over the point of puncture andthus complete the healing operation.'

By providing an inner coatin of libere which will form a mat when t etube is inflated, Athe plastic sticky compound is given vthe necessarysupport or re-enforcement to the air would tend to shift only that portion of the compound adjacent the puncture, with the result that thecompound would in many pases be blown throu h the puncture and thesealing action wou d not be as reliable or ellicient as in the presentcase, and, in fact, would not take place at all should a large puncturebe made Vin the tube. The fibers when matted as described areadvantageous as compared with a fabric inner coating because they do notlimit the flowing action of the compound or in any Way interfere withthe expansion or the compression of the tube within the casing of t etire when the tube is inflated. 1n other words the tube will operatejust as efficiently in an oversized casing as in an undersized pasng. l

It has been found that by combining with the plastic compound a volatilesubstance or a substance that will dry guickly when exposed to air, asfor examp seed oil, albumen, gum arabic or the like, the exudation ofcom und produced by the sealing of the tube will become dry and thuseffect a permanent seal which will enable `the tube to be removed fromone casing,

e pitch, linafter bein punctured and used in another only vegetable ormineral'iibers in the forp 'l mation of this tube.

lWhat is claimed is A self healing'dinner tube for pneumatic fibers losirav

tires comprising a wall of cured rubber, a solid layer of sticky plasticcompound upon the inner surface of said wall at the tread portionthereof, and an inner coatin of matted loose fibers lying flat upon an.ad-

hering to the inner or exposed surface of l said compound. y

In testimony that l claim the foregoing as my own, I have hereto allixedmy sig nature in the presence of a witness.

NATHANEL G. WARTH.l Witness HERBERT D., LAWSON.

